taken 7 years ago, near to Benllech, Isle of Anglesey/Sir Ynys Mon, Great Britain

More Ancient Potholes

The headland here is covered with these curiously-shaped holes, some with rocks like mushrooms growing from the solid surface. They are the tops of sandstone-filled potholes like the one in this image SH5381 : Section Through a Pothole. The sandstone is more resistant to erosion by the sea than the limestone beneath, so it remains, sometimes protruding above the limestone where it has been eroded away.